The outcome of President Reagan's drive to persuade Congress to resume aid to Nicaraguan rebels is likely to determine whether Reagan moderates his tough line toward Nicaragua's Sandinista government or sticks with policies leading to prolonged civil war in Central America, Nicaraguan Deputy Foreign Minister Victor Hugo Tinoco said yesterday.

Tinoco, who is here to lobby selected members of Congress, said a continued ban on covert aid to the rebels, known as "contras," could force Reagan to abandon his determination to make the Nicaraguan government cry "uncle," as the president put it at a news conference last week.

"If he gets the money, the civil war in Nicaragua will go on for two or three more years, and it will mean continued suffering for the people of Nicaragua, and it will affect the other countries of Central America," Tinoco said in a meeting with Washington Post editors and reporters.

"If not, it will be almost as if Congress is saying to President Reagan that he has to change his policy toward the region," he added. "What the Congress does could almost be called a turning point . . . ."

The importance the leftist Sandinista government attaches to the fight over renewed U.S. funding for the contras was underscored by its unusual decision to send Tinoco here at a time of heightened tension in U.S.-Nicaraguan relations.

Tinoco declined to identify which members of Congress he hopes to see on grounds that many of his requests for appointments are pending. Thus it was not clear whether he will be able to talk with a significant cross section of Congress or blunt the administration's campaign to induce Congress to release $14 million in covert-action funds blocked last spring.

At Reagan's news conference Thursday, he said his goal was to "remove" the "present structure" of the Nicaraguan government. On Friday, Secretary of State George P. Shultz, calling the contras "freedom fighters," said they were the only force capable of ending the Sandinistas' "role as a surrogate for the Soviet Union and Cuba" and warned that failure to help the contras would condemn Nicaragua "to the endless darkness of communist tyranny."

Tinoco, who called the remarks by Reagan and Shultz "a rhetorical offensive," said he does not believe that U.S. forces can invade Nicaragua because it would have adverse effects throughout Latin America and Europe. "We don't see that Reagan is creating the conditions internationally that would establish a climate for invasion," he said.

But, he added, as long as the administration adheres to its position that "the Sandinista revolution must be overthrown," there is no possibility of improved relations between the United States and Nicaragua. He said continued U.S.-Nicaraguan tensions also would prevent progress in the so-called Contadora effort to end conflicts between Nicaragua and such Central American neighbors as El Salvador, Honduras and Costa Rica.

Tinoco said the United States suspended the talks he was conducting in Mexico with U.S. special envoy Harry W. Shlaudeman because they had reached the point "where it was not possible to avoid concessions on both sides, and the United States doesn't contemplate making any concessions."

The administration has said it stopped participating in the talks because it believed that Nicaragua was using them to avoid acceptance of the Contadora process. Tinoco said, however, that Nicaragua had offered to make concessions in the Contadora talks on all points of importance to the United States and had been rebuffed.

As a result, he said, "the whole process is stalemated, both bilaterally and multilaterally. Contadora cannot work if the U.S. administration refuses to accept the Nicaraguan revolution as it is and continues to pay mercenaries to try to overthrow the revolution."